A shrub or bush is a horticultural rather than strictly botanical category of woody plant, distinguished from a tree by its multiple stems and lower height, usually less than 5-6 meters (15-20 feet). A large number of plants can be either shrubs or trees, depending on the growing conditions they experience. Small, low shrubs such as lavender, periwinkle and thyme are often termed subshrubs.
An area of cultivated shrubs in a park or garden is known as a shrubbery. When clipped as topiary, shrubs generally have dense foliage and many small leafy branches growing close together. Many shrubs respond well to renewal pruning, in which hard cutting back to a ‘stool’ results in long new stems known as “canes”. Other shrubs respond better to selective pruning to reveal their structure and character.
Shrubs in common garden practice are generally broad-leaved plants, though some smaller conifers such as Mountain Pine and Common Juniper are also shrubby in structure. Shrubs can be either deciduous or evergreen.
Homeowners, foresters, agriculturists, landscape workers and the like often need to permanently remove unwanted shrubs, bushes and small trees. Rangers and volunteers who care for public park woodlands face an ongoing need to remove invading exotic shrubs and bushes disrupting the balanced ecosystem of native plant varieties. Problems associated with clearing young shrubs and woody bushes from an area have involved back-breaking toil, using picks and shovels to uncover the roots and then pulling by hand or with the help of draft animals, or in more modern times with tractors and winches. While this approach was effective, it was laborious, it required considerable physical strength, and it disturbed a much larger area than the plant occupied.
Another approach was to cut the plant at the soil line using one of a variety of hand or fuel-powered blade tools, leaving the plant's root system intact beneath the surface. This left an area looking cleared with a minimum of disturbance to the surroundings, but soon new growth would appear from the old roots, and the plant would come back bushier and more difficult to remove than before. Furthermore, blade tools required strength and skill to use; fuel-powered tools provided noise and fumes, as well as high purchase and maintenance costs.
A third approach was to use herbicides to kill the unwanted shrub or bush. A trained operator used expensive and potentially hazardous chemicals in a spraying apparatus to poison the target plant. The nearby desirable plants were often harmed by overspray of the herbicide. When the target plant was dead, there still remained the problem of extracting it. Many questions remain about the long-term effects of herbicides on humans, wild animals and the environment. Therefore, public park agencies and property owners have become reluctant to use chemical herbicides. Parks in particular use chemicals only as a last resort rather than provoke public outrage.
Most users, therefore, would find it desirable to have a tool which could grip an unwanted shrub or bush and uproot it completely, easily and safely without undue disturbance to neighboring vegetation or harm to the user or to the environment. It would also be desirable to provide a tool for easily grasping and uprooting shrubs, bushes or small trees; to provide such a tool which can be effectively and safely operated by a person of ordinary physical strength and with little training or experience; to provide such a tool which acts selectively on the target plant with minimum disturbance to surrounding vegetation; to provide such a tool which extracts sufficient root to kill the plant, leaving nothing to re-sprout later; and to provide such a tool which requires no chemicals for its effective operation. It would be further desirable to provide a tool which is easily carried to the site of operation; to provide such a tool which requires little storage space and minimal maintenance.